Fluid-assisted medical device

ABSTRACT

The invention provides a medical device that includes a housing, a tubular member extending from the distal end of the housing, a first arm extending from the distal end of the tubular member, the first arm including a first electrode, a second arm extending from the distal end of the tubular member, the second arm including a second electrode and being disposed coaxially with the first arm, at least one solution infusion opening on each electrode, and a solution delivery channel for delivery of a conductive solution to the solution infusion openings. According to the invention, at least one of the first arm or the second arm is translationally moveable, and at least one of the first arm or the second arm is adapted to be coupled to a source of radiofrequency energy. The invention also provides a corresponding method for treating blood vessels or other tissues of the body.

This application is a continuation of application Ser. No. 09/668,403,filed Sep. 22, 2000 now U.S. Pat. No. 6,558,385, which application(s)are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to the field of devices for use insurgery upon tissues of the body. More particularly, the inventionrelates to an electrosurgical device and methods of treatment of bodytissues.

BACKGROUND OF THE INVENTION

Electrosurgical devices use electrical energy, most commonlyradiofrequency (RF) energy, to cut tissue and/or cauterize bloodvessels. During use, a voltage gradient is created at the tip of thedevice, thereby inducing current flow and related heat generation in thetissue. With sufficiently high levels of electrical energy, the heatgenerated is sufficient to cut the tissue and, advantageously, tocauterize severed blood vessels.

Current electrosurgical devices can cause the temperature of tissuebeing treated to rise significantly higher than 100° C., resulting intissue desiccation, tissue sticking to the electrodes, tissueperforation, char formation and smoke generation. Peak tissuetemperatures as a result of RF treatment of target tissue can be as highas 350° C., and such high temperatures may be transmitted to adjacenttissue via thermal diffusion. Undesirable results of such transmissionto adjacent tissue include unintended thermal damage to the tissue.

One limitation of current electrosurgical devices arises from sizeconstraints and dimensions. It is difficult to reach or gain access tosome tissue and vessels due to anatomy and size constraints.Electrosurgical devices often have movable hinged scissors-like jaws attheir tip that must open widely to be placed around the target tissue tobe treated. Hinged jaws reduce visibility of the tip and often limitgrasping capability of vessels due to force constraints. Further,devices currently used also often have long rigid shafts that cannotbend to maneuver around anatomical “tight” spots.

Laparoscopic or minimally-invasive surgery often involves multipleinstrument passes through a trocar to achieve the desired tissue effect.Separate instruments are often required for coagulation and for cutting.Separate instruments may also be required to achieve surface hemostasis,such as when there is bleeding from the surface of an organ such as theliver. Multiple instrument passes are undesirable because they (1) wastevaluable operating room time, (2) sometimes make it difficult toprecisely relocate the target treatment site, (3) increase the risk ofinfection, and (4) increase the cost by increasing the number ofdifferent surgical instruments that are needed to complete the surgicalprocedure.

Accordingly, there is a need for a surgical device that reducesundesirable effects such as tissue desiccation and resulting tissuedamage, char formation, smoke generation, and risk of infection, whileat the same time providing improved accessibility to tissues andefficiency.

SUMMARY OF THE INVENTION

The invention provides an improved electrosurgical device forcoagulating and cutting tissues of the body, utilizing the simultaneousinfusion of a conductive solution and application of RF energy. This isaccomplished with a device that includes a first electrode positioned ona first arm, and a second electrode positioned on a second arm, whereinat least one of the first arm or the second arm is translationallymovable, and at least one of the first electrode or the second electrodeis adapted to be coupled to a source of radiofrequency energy. The firstarm and the second arm are coaxially arranged. In a preferredembodiment, the device comprises a housing having a proximal and adistal end; a tubular member having a proximal and a distal end, thetubular member extending from the distal end of the housing; a first,translationally movable arm extending from the distal end of the tubularmember, the first arm including a first electrode; a second armextending from the distal end of the tubular member, the second armincluding a second electrode and being disposed coaxially with the firstarm; at least one solution infusion opening on each electrode; and asolution delivery channel for delivery of a conductive solution to thesolution infusion openings, wherein at least one of the first electrodeor the second electrode is adapted to be coupled to a source of RFenergy.

In a preferred embodiment, the first arm and second arm include at leastone groove that surrounds the at least one solution infusion opening.Preferably, the groove(s) include spaced exit slots to allow conductivesolution to exit the groove during use (e.g., when pressure is appliedto tissues). The grooved arm serves to isolate the metal electrode fromdirect contact with bodily tissues being treated. Additionally, thegrooved configuration provides constant spacing between the electrodeand tissue to be treated. Further, the groove assists in preventingtissue pressure against the solution infusion openings during squeezingof the arms of the device, which could inhibit or reduce the flow ofelectrically conductive fluid locally.

Preferably, the device further comprises a translationally movablecutting mechanism to transect tissue after it has been coagulated. Thedevice can also be used to achieve surface hemostasis with no specialadjustments or removal of the instrument from the patient.

In a preferred embodiment, the device further includes a lockingmechanism, to selectively lock one or both of the arms of the device ina desired position.

The invention also provides a corresponding method for treating tissuesof the body, including, for example, blood vessels. The invention isuseful for ligating and dividing a dorsal vein or other blood vesselsthat are located in deep cavities of the body, as well as for proceduresinvolving polyp removal and laparoscopic tubal ligations.

The invention provides a combination of advantages. For example, thedevice provides conductive solution, such as saline, at theelectrode-tissue interface to limit the peak tissue temperature,preferably to 100° C. or less. The provision of saline at the interfaceprevents tissue desiccation and the various effects of desiccation, suchas tissue sticking to the electrodes, perforation of adjacent organs ortissue structures, char formation on electrodes and adjacent tissue, andsmoke formation. The saline at the interface preferably maintains peaktissue temperature at or below 100° C. by (1) providing coupling of theelectrode to the tissue with a wetted contact area that is much largerthan that of a dry electrode, thus reducing current density and local RFheating near the electrode-tissue interface, (2) providing a convectivecooling effect, such that the flowing liquid saline is heated by thewarmer surface of RF-heated tissue, and (3) providing an evaporativecooling effect, such that excess RF power that cannot be conducted orconvected away from the target tissue will be used to boil some fractionof the saline provided to the treatment surface.

The invention also provides an instrument that has a lower profile thanstandard coagulating forceps with hinged jaws. In a preferredembodiment, the device includes a tubular member that has anarticulating or bending feature to enable the distal end effector regionof the device, including first and second arms, to pass aroundanatomical features. According to the invention, the device is capableof being made with an outside diameter that is 25 mm or less.Preferably, the device is capable of being made with an outside diameterthat is 15 mm or less, more preferably 5 mm or less. As used herein, theoutside diameter is the maximum size that the tubular member or firstand second arms achieve as a result of device operation.

The invention further provides a multi-purpose instrument that can beused to provide both coagulation and cutting of tissue without having tobe removed from the patient's body. In one embodiment, the instrument isfabricated so that it is capable of sealing and cutting a vessel, aswell as causing surface hemostasis on tissue such as bleeding liver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a device according to one embodiment of theinvention.

FIG. 2 is an open side view of the device of FIG. 1.

FIG. 3 is an enlarged side cross-sectional view of the distal end of thedevice of FIG. 1.

FIG. 4 is a perspective view of one embodiment of first and secondelectrodes of the invention.

FIG. 5 is a perspective view showing the operation of the device of FIG.4 at a surgical site.

FIG. 6 is side view of the distal end of one embodiment of theinvention.

FIG. 7 is a side view of the embodiment shown in FIG. 6, demonstratingthe operation of the device at a surgical site.

FIG. 8 is a side view of the embodiment shown in FIG. 6, demonstratingthe operation of the device including a cutting mechanism at a surgicalsite.

FIG. 9 is a top view of the embodiment shown in FIG. 6, wherein thefirst electrode and cutting mechanism are retracted.

FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. 9.

FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 9.

FIG. 12 is an end view of an embodiment of a grooved arm of theinvention.

FIG. 13 is a side view of the embodiment shown in FIG. 12, showing anembodiment of the device with a plurality of exit slots from a groove.

FIG. 14 is a cross-sectional view taken along line 14-14 of FIG. 13.

FIG. 15 is a top view of the distal end of the device, demonstratingoperation of the device of FIG. 6.

FIG. 16 is a top view of the distal end of the device, demonstratingoperation of the device of FIG.6.

FIG. 17 is a cross-sectional view taken along line 17-17 of FIG. 16.

FIG. 18 is a cross-sectional view taken along line 18-18 of FIG. 16.

FIG. 19 is an enlarged cross-sectional view taken along line 17-17 ofFIG. 16, demonstrating saline flow and current paths during RFapplication.

FIG. 20 is a side cross-sectional view of the one embodiment of thedevice, including porous metal electrodes.

FIG. 21 is a side cross-sectional view of an alternative embodiment ofthe device, including porous polymer electrodes.

FIGS. 22 a and 22 b are schematic side views of two embodiments of theelectrical connections to the arms and/or the cutting mechanism of thedevice.

FIGS. 23 a-23 e show various shapes for the cutting mechanism of theinvention.

FIG. 24 is a perspective view of an alternative embodiment of theelectrode of the invention.

FIG. 25 is a perspective view of the embodiment of FIG. 24, showingtreatment of a blood vessel.

FIGS. 26 a-26 b show the coagulation and cutting pattern for a smallvessel according to one embodiment of the invention.

FIGS. 27 a-27 d show the coagulation and cutting pattern for a largervessel according to one embodiment of the invention.

FIG. 28 shows one embodiment of the device involving coagulative surface“painting” with no tissue between the electrodes.

FIG. 29 is a side view of one embodiment of the invention, including anarticulating tubular member.

FIG. 30 is a top view of the embodiment of FIG. 29.

FIG. 31 is a top view of an alternative embodiment of the device,including a second electrode as a ball tip.

FIG. 32 is a top view of the device shown in FIG. 31, demonstratingoperation of the device.

FIG. 33 is a side cross-sectional view of the embodiment shown in FIG.31

FIG. 34 is a side cross-sectional view of the embodiment shown in FIG.32.

FIG. 35 is a top view of one embodiment of the invention.

FIG. 36 is a cross-sectional view along line 36-36 of FIG. 35.

FIG. 37 is a cross-sectional view along line 37-37 of FIG. 35.

FIG. 38 is an end view of the embodiment shown in FIG. 35.

FIG. 39 is a side cross-sectional view of an alternative embodiment ofthe device.

DETAILED DESCRIPTION

The invention provides a medical device that comprises a first electrodeand a second electrode, wherein the electrodes are disposed coaxially toeach other, and at least one of the electrodes is translationallymovable. Preferably, the first electrode is provided on a first arm, andthe second electrode is provided on a second arm of the device.According to the invention, the device comprises at least onetranslationally movable arm that can be selectively movable to a fixedposition. Preferably, the device includes a locking mechanism, to allowthe operator to move at least one arm of the device to a desiredposition and lock the arm in that position. Each electrode is providedwith conductive solution. In a preferred embodiment, the electrodesinclude at least one groove to assist in delivery of the conductivesolution to tissue.

In a preferred embodiment, the invention provides a medical devicecomprising a housing having a proximal and a distal end; a tubularmember having a proximal and a distal end, the tubular member extendingfrom the distal end of the housing; a first, translationally movable armextending from the distal end of the tubular member, the first armincluding a first electrode; a second arm extending from the distal endof the tubular member, the second arm including a second electrode andbeing disposed coaxially with the first arm; at least one solutioninfusion opening on each electrode; and a solution delivery channel fordelivery of solution to the solution infusion openings. The device isconfigured such at least one of the first and second arms is adapted tobe coupled to a source of radiofrequency energy. The invention can beused to treat tissues of the body, including blood vessels and surfacesof organs, such as the liver. Although the invention will be describedherein in relation to these mentioned applications, it is understoodthat the device has other applications as well, and these are consideredwithin the scope of the invention.

In the present description, elements in common between the embodimentsof the figures are numbered identically, and such elements need not beseparately discussed.

One preferred embodiment of the device is illustrated in FIG. 1. Asshown in FIG. 1, housing 1 of the device includes an actuation member 2and a trigger 3. Extending from the distal end of the housing is tubularmember 6. Extending from the distal end of the tubular member 6 are thefirst arm containing first electrode 8 and the second arm includingsecond electrode 9, end portion 25, and platform portion 26. The firstarm, second arm, and cutting mechanism 7 together comprise the endeffector region E of the device. In a preferred embodiment, the cuttingmechanism 7 is translationally movable, preferably independently frommovement of the first and second arms. At the proximal end of thehousing is located a solution supply tube 4, which delivers saline orother electrically conductive solution under pressure from a solutionsupply 10 to solution infusion openings located on the electrodes 8 and9. Also at the proximal end of the housing are two conductors 5 thatconduct RF from an RF generator 11 to the electrodes 8 and 9 of thedevice. Each component of the device will now be described in detail.

Referring to FIG. 1, a housing 1 includes two actuators, an actuationmember 2 that controls the translational movement of at least one of thearms, and a trigger 3 that controls the translational movement of thecutting mechanism 7. As illustrated, in a typical operation, theactuation member 2 can be actuated by the thumb of the operator, whereasthe trigger 3 can be actuated by the index finger of the operator.However, the precise configuration of the actuation member 2 and trigger3 is not critical to the invention, and other configurations can be usedto achieve translational movement of the cutting mechanism and arms,respectively. Preferably, the first and second arms are independentlymovable from the cutting mechanism, such that the operator canselectively move one or more arms of the device, the cutting mechanism,or all of these components, as desired.

Attached to the distal portion of the housing is the tubular member 6.The tubular member 6 includes a lumen through which the actuation rodsfor the arms and cutting mechanism, the solution delivery channel, andthe conductors pass. Although the dimensions of the tubular member 6 canbe adapted for a desired purpose, the tubular member is preferably long(approximately 10 to approximately 50 cm, preferably approximately 20 cmto approximately 40 cm, more preferably approximately 25 cm toapproximately 35 cm), with a diameter of about 2 mm to about 20 mm,preferably about 3 mm to about 10 mm. In one embodiment, the tubularmember 6 is circular in outer shape and rigid, so as to pass easilythrough a trocar. Alternatively, the tubular member 6 is malleable. Inyet another embodiment, the tubular member includes a deflectable tipthat can be controlled by the surgeon during use, e.g., by using a wireconnected to the tip that can be pulled to deflect the tip to one side.

At the most distal end of the tubular member 6 is located the endeffector region E, comprising a collection of components that functiontogether to cause the desired tissue effects to occur. This end effectorregion E of components consists of the cutting mechanism 7, the firstarm with first electrode 8 and the second arm with second electrode 9,and is shown circled in FIG. 1.

At the proximal portion of the housing is located the fluid supply tube4, which contains saline or other electrically conductive solution suchthat the fluid flows into the solution supply channel in the housingfrom a source 10 such as an intravenous bag of solution hung from anintravenous (IV) pole, a pressurized elastomeric canister, a syringepump, an intravenous volumetric infusion pump, or a peristaltic pump.Other configurations of supply sources can be provided, to achieve thepurposes described herein. Also at the proximal portion of the housingare two wires 5, which are connected to a radiofrequency generator 11such that electrical power is supplied to the device. It is contemplatedthat the device can include one cable that connects the radiofrequencygenerator to the electrodes of the device. The electrical connection canbe made to be switched with a foot switch, a hand switch or both.

In one embodiment, the solution supply source 10 comprises a pressurizedcanister that can be adapted to be received within the housing 1, or itcan be provided externally. When the solution supply source is receivedwithin the housing 1, the portion of the fluid supply tube that extendsfrom the proximal portion of the housing can preferably be eliminated.In a further embodiment, the solution supply source can be attached tothe exterior of the housing. The provision of the solution supply sourceas an internal component of the device, or as a component attachable tothe exterior of the housing, thus preferably eliminates the “tethering”effect of a solution supply tube that runs from the proximal portion ofthe housing to an external supply source that is separate from thehousing.

In yet another embodiment, the housing 1 may contain an electricalswitch to turn the solution supply source on or off.

In still another embodiment, the housing 1 can contain a mechanicalvalve or flow control device, such that moving a linear or rotatingpiece from one position to another increases or decreases the flowresistance, and hence the flow rate of solution. Such a valve can becontinuously adjustable or can be arranged to provide a series ofpre-set levels of flow resistance such that the flow rate can beadjusted in fixed increments.

Additionally, the solution could be provided at a much higher “flush”rate that can be selected using an electrical switch located on thehousing 1, or via a foot switch. Similarly, an additional tube can beprovided to the distal region of the device to provide suction torapidly remove accumulated blood, saline or other fluid in the operativesite. In one embodiment, suction at the tip is activated by occluding asmall circular opening located on the housing 1 (e.g., by virtue of theoperator using a finger to cover the hole when suction is desired). Withthe suction always turned on, occluding the hole enables the suction“intake” to move from the hole in the housing to the tip of the device.

FIG. 2 shows an “open” side view of the device. “Open” in this contextmeans that this is not precisely a cross-sectional view with cut-awayfaces of internal components. FIG. 2 illustrates one embodiment of howthe actuators connect to components in the end effector of the device.Actuation member 2 is slidably disposed within a slot formed in thehousing 1. Within the housing 1, the actuation member 2 is connected toa proximal end of an arm actuation rod 12, which runs from the actuationmember within the housing and through the entire length of the tubularmember 6.

In the embodiment shown in FIG. 2, at its distal end, the arm actuationrod 12 is connected to the first arm, which includes first electrode 8.Arm actuation rod 12 is connected to the first arm through crimping orother conventional connectors, or may be integrally formed with thefirst arm. Movement of the actuation member 2 in the distal directioncauses corresponding distal movement of the arm actuation rod 12 withintubular member 6, which results in corresponding distal movement of thefirst arm; conversely, movement of the actuation member 2 in theproximal direction causes corresponding proximal movement of the armactuation rod 12, which results in corresponding proximal movement ofthe first arm. As the first arm moves distally, it decreases thedistance between the first arm and second arm, thereby compressing ablood vessel or other piece of tissue between the first arm and thesecond arm. In the embodiment shown, the second arm 9 is stationary.

With continuing reference to FIG. 2, cutting mechanism 7 is connected atis proximal end to cutting actuation rod 15 through crimping or otherconventional connectors. The distal end of cutting actuation rod 15 isattached to cutting mechanism 7 by, for example, crimping, soldering,pinning, and the like, and the proximal end of the cutting actuation rod15 is located within housing 1. At or near its proximal end, cuttingactuation rod 15 includes gear rack 14. Trigger 3 is provided withpinion 13 that includes gear teeth which engage the gear rack 14. Whentrigger 3 is moved in the direction of arrow A, pinion 13 rotates andengages gear rack 14. The meshing of the gear teeth of pinion 13 and thegear rack 14 causes the cutting actuation rod 15 to move distally withintubular member 6. This, in turn, causes distal movement of cuttingactuation rod 15, extending the cutting mechanism 7 distally from thedevice.

At its proximal end, gear rack 14 is operably connected to spring 16.Spring 16 is secured within housing 1 to anchor it in a desiredlocation. Spring 16 serves to bias (e.g., push or force) cuttingmechanism 7 proximally, thus returning the cutting mechanism 7 to aretracted position when trigger 3 is released, as shown in FIG. 2.Preferably, gear rack 14 further includes ridge 17, which serves as alimiter of distal cutting mechanism movement when it comes into contactwith stop 18. Stop 18 is located within housing 1 at a position that isdistal relative to gear rack 14. Thus, when trigger 3 is moved in thedirection of arrow A, thereby rotating pinion 13 which engages gear rack14, the gear rack 14, along with cutting actuation rod 15, moves in thedistal direction. Distal movement of the gear rack 14 and cuttingactuation rod 15 is stopped by contact of ridge 17 with stop 18. Thepurpose of the limiting mechanism described is to limit distal movementof the cutting mechanism 7, such that it does not come into contact withthe second arm or second electrode, or extend distally beyond the secondarm, thereby cutting tissue that may not be treated with the electrodesand thereby coagulated. It is to be understood that modifications to thelimiter mechanism described herein can be made without departing fromthe invention. It is apparent that the gear ratio, not shown to scale,is described to close the electrodes with less than a 180° travel.

Tubular member 6 extends from the distal end of the housing 1. Tubularmember 6 is preferably made from a non-conductive polymer material suchas polycarbonate, LCP (liquid crystal polymer) or other extrudablematerial that has moderate to high temperature resistance.Alternatively, tubular member 6 is fabricated from a metal, such asstainless steel or the like, and coated with a polymer materialmentioned above. Tubular member 6 includes a lumen, though which thecutting actuation rod 15, arm actuation rod 12, solution deliverychannel 4 and conductors 5 pass. The outside diameter of tubular member6 is preferably of a size for passing through a cannula and the lengthis sufficient to reach an internal blood vessel to be cauterized ortissue to be treated when the tubular member is slidably insertedthrough the cannula and into the body of a patient, as discussed above.

Tubular member 6 may be integrally formed with the housing 1, or it maybe secured to housing 1 in a suitable manner, such as with adhesives, orusing such techniques as press-fit, heat-staking or ultrasonic welding.

The device includes end effector region, as shown labeled in the figuresas E, which will now be described in more detail. The device of theinvention provides a first, translationally movable arm and a second armthat is disposed coaxially with the first arm. As used herein,“coaxially” means the first arm and second arm are configured in aside-by-side arrangement, so that the arms extend in a parallel mannerfrom the distal end of the tubular member 6. As discussed herein, thefirst arm of the device includes first electrode 8, and the second armincludes a second electrode 9. Thus, as the first arm moves in thedistal direction, it approaches the second arm of the device. As eacharm includes its respective electrode, movement of the first arm, withits first electrode, towards the second arm, with its second electrode,allows the user to grasp tissue to be treated with the arms and apply RFenergy to treat the tissue as desired.

FIG. 3 illustrates an enlarged view of the end effector region E of oneembodiment of the invention. The end effector region of the deviceincludes the first arm including first electrode 8, the second armincluding second electrode 9, and an optional cutting mechanism 7(described in more detail below).

According to a preferred embodiment of the invention, each arm of thedevice is provided with its own solution delivery channel and conductor.As shown in FIG. 3, a solution delivery channel 4 is located within thetubular member 6. The solution delivery channel 4 extends from asolution source 10 at its proximal end, to the end effector region ofthe device at its distal end. In one embodiment, the device includes aseparate solution delivery channel for each arm of the device.Alternatively, as shown in FIG. 3, the device includes a single solutiondelivery channel 4 that splits within the tube 6 toward the distal endof the tube. The “split” solution delivery channel thus forks to formfirst tube 20 that is in fluid communication with the first arm, andsecond tube 21 that is in fluid communication with the second arm. Asshown in FIG. 3, first tube 20 is somewhat coiled and has slack in it sothat when the first arm moves translationally, the first tube 20 canaccommodate the motion without stretching or kinking. The preciseconfiguration of solution delivery channel 4 is not critical, and it isunderstood that modifications can be made to the embodiment shown tosupply conductive solution to the first arm and second arm of thedevice.

In addition to including a solution delivery channel, each arm of thedevice preferably includes a conductor for conducting RF energy from asource to the electrodes. As shown in FIG. 3, conductor 22 (shown inbroken lines) is in communication with the first arm and thus firstelectrode 8, and conductor 23 (shown in broken lines) is incommunication with the second arm and second electrode 9. The conductors22, 23 are connected to a source of energy 11, such as RF energy, attheir proximal ends. At their distal ends, each conductor is connectedwith an electrode of an arm of the end effector region E. Conductors 22and 23 can be provided in the form of wires or other suitable conductivematerials. As shown in FIG. 3, conductor 22 can be configured to includesome coiling and slack to accommodate the translational movement of thefirst arm. Each of the conductors, 22 and 23, are preferably insulatedby a sheath of non-conductive polymer such as Teflon™, with theinsulation in place everywhere along the wires except where the wiresare connected to other components, where the insulation is stripped toenable good crimps, solders or other connectors. Other suitableinsulation can be applied to the conductors and their connections.

FIG. 4 illustrates a perspective view of an embodiment of an endeffector region of the device, including first and second electrodes, aswell as a cutting mechanism. According to a preferred embodiment of theinvention, the first and second electrodes, 8 and 9 respectively, aresimilar in shape and construction. Preferably, the first and secondelectrodes are substantially similar in size and dimensions. In oneembodiment, for example, the first and second electrodes are provided ina 1:1 size ratio. In a preferred embodiment, each electrode has both anelectrical connection and a solution connection, as discussed herein.One way to accomplish this is to use hollow stainless steel needle(e.g., hypodermic) tubing as the structural foundation of the electrode.As shown in FIG. 4, the electrode loop is similar to a rectangle whichis bent up at one end. Preferably, when the electrode loop is bent, theangle formed by the bent loop is 90°. At the proximal end of theelectrode, both the electrical and fluid connections are made. Theelectrical connection is made via a crimped or soldered connection ofthe inner braid of low resistance wire to the metal of the stainlesssteel tubing. The solution connection is such that the flow ofelectrically conductive fluid travels from a flexible polymer tubing(such as Tygon™ (PVC), Teflon™, and the like) to the stainless steelneedle tubing. Once the electrical connection is made at the proximalend of the loop, electrical energy is conducted along the steel tubingwithout any significant loss in voltage or power. In the embodimentshown in FIG. 4, the conductive solution flows in both legs of thetubing, reaching the bent-up loop end where the solution leaves themetal tubing.

FIG. 5 is another perspective view showing two electrodes along with ablood vessel to be treated, and a cutting mechanism 7. As shown, thefirst electrode 8 and second electrode 9 can be used to grasp a bloodvessel, shown in broken lines (or other tissue), during treatment. Asdescribed herein, the cutting mechanism can move translationally,whereas either or both of the first arm containing the first electrode,and the second arm containing the second electrode, can be stationary ortranslationally movable, as desired. According to the invention, atleast one arm of the device is translationally movable.

FIG. 6 shows a side view of the end effector region of the device, withthe first arm and the cutting mechanism 7 both fully retracted (i.e.,located at a proximal, unextended position). The second arm is shownincluding a portion of exposed metal 9, representing the secondelectrode, an end portion of the arm 25, and an underside, or platformportion 26. As shown in FIG. 6, the second electrode 9 is insulated andthe end portion 25 and platform portion 26 of the second arm are bothfabricated of non-electrically conductive polymer. End portion 25 andplatform portion 26 together form a right angle in this embodiment. Thetissue, such as a blood vessel, to be compressed and treated with RF isshown in cross-section as 24. FIG. 7 shows the embodiment of FIG. 6,wherein the first arm has been advanced distally to compress the vessel24. FIGS. 6 and 7 show the cutting mechanism 7 in a retracted, or fullyproximal, position.

FIG. 8 shows another side view of the end effector region of the deviceafter the cutting mechanism 7 has been fully advanced distally to cutthrough the compressed vessel 24. The broken lines show the position ofthe cutting mechanism within the device. As discussed herein, a stoplocated inside the housing preferably limits the distal motion of thecutting mechanism so that it does not come into contact with, or extendbeyond, the distal edge of the second arm. Preferably, the first andsecond arms of the device include a guide slot to allow translationalmovement of the cutting mechanism, as discussed in more detail below.

FIG. 9 shows a top view of the end effector embodiment shown in FIG. 9.The cutting mechanism 7 and the first arm are shown in a retracted, orfully proximal, position. In one preferred embodiment, the second armincludes a platform portion 26 that comprises a generally flattened arealocated proximal the bent portion of the arm. The platform portion 26 isconfigured to accommodate tissue, such as a blood vessel, to be treatedwith the device. At the same time, the platform portion 26 is limited bythe diameter of the tubular member 6, so that the second arm is capableof freely translating in the proximal and distal directions within thetubular member 6. The platform portion 26 can be used to hold a vesselor tissue to be treated in position prior to compression and RFtreatment. Preferably, the platform portion 26 includes a guide slot 27,to allow translational movement of the cutting mechanism 7. Whenincluded in the device, guide slot 27 stabilizes and guides the cuttingmechanism in a straight path when it is moved distally toward the secondarm. In the embodiment shown in FIG. 9, the distal arm is preferablyinsulated to avoid treating tissue that is not positioned between thetwo arms of the device.

FIG. 10 shows a cross-sectional view along line 10-10 of FIG. 9. Thisview looks toward the proximal direction of the device, down the axis ofthe tubular member 6 toward the housing 1. In this embodiment, first armis shown including a “U” shaped electrode 8 on its face. A series ofsmall diameter holes that define solution infusion openings 28 areoriented around the surface of the first electrode 8. The entire surfaceof the first electrode 8 that is shown in this figure is exposed metalthat may conduct electrical energy to tissue. Cutting mechanism 7 isseen with the sharp edge being the line down the middle of thecenterline of the figure. The platform portion 26 that supports thesecond electrode is made of a non-conductive material such as a polymeror ceramic. Two legs of the second electrode loop tubing are buried inthe platform portion 26, each shown with a thin wall 29 of stainlesssteel or other electrically conductive material, and a solution deliverytube 21 to convey saline or other electrically conductive fluid to thedistal electrode. The solution delivery tube 21 comprises the distalportion of solution supply tube 4 of the device.

FIG. 11 shows a cross-sectional view along line 11-11 of FIG. 9. Thisview looks toward the distal end of the device, facing the exposed metalportion of the second, stationary electrode. In this embodiment, theshape of the distal electrode “bent-up” loop is “U” shaped, with aseries of small diameter holes that define solution infusion openings 31oriented around the surface of the electrode. Gap 32 indicates where thedistal tip of the cutting mechanism (not shown) travels. The guide slot27 that holds the lower part of the cutting mechanism is shown here incross-section. In this embodiment, the platform portion 26 is shown ascontaining two tubing sections, each with a thin wall 29 and a solutiondelivery tube 21.

Solution infusion openings, in the form of a series of finelaser-drilled holes, each with a diameter of about 0.001 to about 0.010inches, preferably about 0.005 to about 0.007 inches, allows thesolution to exit the tubing. In an alternative embodiment, the solutioninfusion openings are formed by electrical discharge machining (EDM),chemical treatment, etching of the metal, or any suitable method forforming holes of the desired size in the tubing. Solution infusionopenings are provided at sufficient intervals along the face of theelectrode that will contact tissue to provide the desired effect.Preferably, the metal tubing is insulated everywhere except where it isdesired that electrical energy be conducted to tissue. Preferably, atleast one electrode is insulated.

The dimensions of the holes or openings and the spacing between holes,as well as the tubing inside diameter and tubing wall thickness arechosen so that the flow of saline is reasonably well distributed to allthe openings. If the resistance to flow down the lumen of the tubing issmall compared to the resistance to flow through an individual hole oropening, then all holes will provide sufficient flow for proper deviceoperation. Generally, resistance to flow is inversely proportional tothe fourth power of the diameter of the lumen or hole, so that doublingthe size of the opening reduces resistance to flow to 1/16th of theinitial value. Typically, the inside diameter of the tubing would rangefrom 0.02 to 0.1 inches and wall thickness would range from 0.004 to0.01 inches. However, it is understood that these measurements can bemodified for a particular application as desired. In a preferredembodiment described in more detail below, solution infusion openingsare included within a groove to achieve flow of conductive solutionthroughout the groove and across the surface of the electrode that isused to treat tissue as described herein.

Referring to FIG. 12, an alternative embodiment of the electrode isshown. In this embodiment, the needle tubing contains one or moreportions where the insulation has been removed, forming an arm having anexposed portion of the electrode 8 that is recessed from the insulatedportions. This results in a electrode having solution infusion openingscontained in a groove 90 of the arm. Preferably, this groovedconfiguration further includes exit slots 92 to allow electricallyconductive fluid to exit the groove and flow freely away from the distalend of the device. In this embodiment, the groove 90 serves to isolatethe metal electrode from direct contact with bodily tissues beingtreated. Additionally, the groove 90 provides constant spacing betweenthe electrode 8 and tissue to be treated. This in turn provides wetelectrical coupling of the electrode to tissue, through the electricallyconductive solution, at a constant distance. Further, the groove assistsin preventing tissue from pressing against and occluding the solutioninfusion openings 28 during squeezing of the arms of the device againsttissue. Such tissue pressure against solution infusion openings 28 couldinhibit or reduce electrically conductive fluid locally. If saline isnot provided at the electrode/tissue interface the proper coupling orconducting of RF electrical energy may not occur.

FIG. 13 shows a side view of multiple exit slots 92 emanating from agrooved electrode configuration as described above and shown in FIG. 12.In this embodiment, the exit slots 92 extend about groove 90 around theinsulated metal electrode tubing to assure that solution can exit fromthe groove 90 without being blocked by compressed tissue. The recessedmetal of the two electrodes 8 and 9 are shown as exposed by these sideexit slots 92.

FIG. 14 shows how the face of the electrode from FIG. 13 appears whenviewed along section 14-14 defined in FIG. 13. Exit slots 92 areprovided in a spaced relation about groove 90 to provide outlet of theconductive solution, and the spacing of the exit slots 92 can beadjusted as desired.

In the embodiments shown in FIGS. 12-14, the exit slots 92 assist inpreventing solution from being trapped in the groove 90. If there were agroove and no exit slots it would still be possible for tissue pressureto inhibit solution flow, since the groove would form a closed spacebetween the electrode and the tissue. Solution pumped into such a closedspace could exit by forcing open a gap between the tissue and theelectrode insulation, for example, when the solution pressure in thespace of the groove exceeded the pressure of the tissue pressing againstthe insulation. Though solution can ultimately leak out as tissue iscoagulated and shrunk, the distribution of solution over the totalelectrode surface can be uneven and result in dry spots where RF energyis not conveyed to tissue as effectively. It is desirable to make theflow rate of solution independent of how hard the tissue is clampedbetween the two electrodes.

A preferred embodiment of the device includes a large number ofrelatively small exit slots, approximately 0.005 inches to approximately0.020 inches wide and from approximately 0.005 inches to approximately0.020 inches deep.

Alternatively, the groove is fabricated from electrically non-conductiveporous polymer or ceramic, preferably polymer or ceramic composed of amaterial that is easily wetted by the electrically conductive solution.In this embodiment, the solution exits through the sides of the grooveby passing through the porous polymer or ceramic material. Wettabilityis usually expressed in terms of the contact angle formed between a dropof liquid lying on a solid surface, with small angles representingbetter wettability than large angles. Using a porous material that ismore wettable reduces the amount of pressure required to initially forcesolution through the fine pores. Teflon™ (polytetrafluoroethylene), forinstance, is not as well wetted by saline as most ceramics, and thuswould be less desirable as a material from which to from the groove.

Using a porous material for the groove creates a very large number ofvery small exit slots, and is one method of providing solution exitsthat provide for uniform flow distribution while also being simple tomanufacture.

It should be understood that there can be more than a single groove onan electrode. If the electrode is more rectangular or square-shaped, itmay be desirable to have a system of criss-crossing or cross-hatchedgrooves evenly distributed over the surface of the electrode. It will beappreciated that the precise pattern of such a plurality of grooves canbe modified to any desired pattern, while maintaining a gap ofconductive solution between metal electrode and tissue that is notsubject to compression by tissue even when the electrodes are pressedfirmly together.

In a preferred embodiment shown in FIGS. 12-14, the first electrode andsecond electrode each contain a groove 90, optionally further includingexit slots 92. Preferably, the configuration of the groove 90 and exitslots 92 (when provided) are mirror images on the first and secondelectrodes.

Slightly prior to and during RF application, a flow rate of conductivefluid, such as physiologic saline (“normal” saline, or 0.9% NaClsolution) or lactated Ringer's™, is provided so that a total flow rateof about 0.1 to 10 cc/min is flowing from laser-drilled holes located onthe proximal and distal electrodes. Preferably, a total flow rate ofabout 0.5 to 2 cc/min is flowing from the laser-drilled holes. Othersuitable conductive solutions include hypertonic saline and Ringer's™solution.

In use, the first, translationally movable arm containing firstelectrode 8 is moved in a distal direction toward the second, stationaryarm containing second electrode 9. FIG. 15 shows a top view of the endeffector region of the device during use, showing the first electrode 8and the second electrode 9 in position so that the blood vessel 24 isjust in contact with each electrode. In this view, the blood vessel iscaptured between the arms of the device so that it is in contact withthe electrodes of the device. The cutting mechanism 7 is shown aspartially advanced from the tubular member.

FIG. 16 shows another top view of the end effector region after thefirst arm has been advanced as far in the distal direction as it can go,resulting in the compression of the blood vessel 24 against the secondarm.

FIG. 17 shows a cross-sectional view along line 17-17 of FIG. 16. Onelumen 33 of the first electrode 8 is shown, being very similar to one ofthe lumens 30 that supply the distal electrode 9. The small diameterholes (solution infusion openings 28 for the first electrode and 31 forthe second electrode) are located so that saline or other conductivesolution is supplied to the electrode-tissue interface. The insulation25 that covers the distal end of the second arm is also shown in thissection. FIG. 18 shows a cross-sectional view along line 18-18 of FIG.16. As shown in FIGS. 17 and 18, lumens 33 and 30 are shown passingthrough the metal tubing of each of the first and second arms which, asindicated in the application above, may provide the structuralfoundation of electrode 8 and electrode 9.

FIG. 19 shows an enlarged cross-sectional view along line 17-17 of FIG.16, with conductive solution flowing and RF electrical energy beingapplied. Conductive solution is indicated by the small arrows 34 flowingthrough one of two lumens and then through a number of solution infusionopenings 28. In this view, the blood vessel 24 is separated from boththe first electrode 8 and second electrode 9 by a gap 38 that is filledwith conductive solution. The conductive solution is therefore acoupling agent that is most often between the metal of the electrodesand the tissue. The free surface or interface of the conductive solutionand the air is indicated at 35. When a differential high frequencyvoltage is applied across the electrodes (8 and 9) current flows asshown by the thicker arrows 36. It will be appreciated that the gap 38need not exist everywhere between the tissue and metal electrodes.

Some of the current may flow between the two electrodes without passingthrough the blood vessel 24, by only passing through a film ofconductive solution. This situation may occur at the edges of the bloodvessel or tissue being treated. The majority of the current willpreferably pass through conductive solution and then through the tissuebeing treated. Under some circumstances the tissue can become hot enoughto have some of the conductive solution boil, as shown by the smallvapor bubbles 37 in the conductive solution film. It will be understoodthat when the device is used as a monopolar device, the solution neednot be delivered to the electrode not in use.

The solution infusion openings of the electrodes supply conductivesolution to the treatment site. In an alternative embodiment, thesesolution infusion openings can be provided in the form of porousmaterial such as metal. In this embodiment, the electrodes do notinclude discrete laser drilled solution infusion openings; rather, theelectrode surface itself is porous to allow infusion of the conductivesolution to the treatment site. Porous sintered metal is available inmany materials (such as, for example, 316L stainless steel, titanium,Ni-Chrome, and the like) and shapes (such as cylinders, discs, plugs,and the like) from companies such as Porvair, located in Henderson, N.C.

Porous metal components can be formed by a sintered metal powder processor by injection molding a two-part combination of metal and a materialthat can be burned off later to form pores that connect (open cell) toeach other. Such methods are known in the art. In this embodiment,conductive fluid will flow out of the electrode everywhere the pores areopen. Preferably, the exterior (i.e., the portions of the componentsthat do not comprise the portion of the device involved in tissuetreatment) of such porous metal electrode components can be covered witha material that fills the pores and prevents both the flow of saline andthe passing of electrical energy.

FIG. 20 shows an enlarged cross-sectional view along line 17-17 of FIG.16. In this embodiment, porous metal 44 comprises both first electrode 8and second electrode 9. A portion of the outer surface of each electrodeis insulated with a non-conductive polymer 45. In this embodiment,conductive solution flow 46 now travels through the porous metal 44 towet the blood vessel 24. The surface of the conductive solution is shownas 35.

In yet another embodiment, a porous polymer is used in place of theporous metal. Although the polymer is non-conductive, the conductivesolution provided will conduct the RF energy across the porous polymerwall and to the tissue to be treated. Suitable materials include hightemperature open cell silicone foam and porous polycarbonates, amongothers. Porous ceramics would also fall into this category, since theycould distribute flow, withstand high temperatures and be machinable ormoldable for manufacturing purposes. Preferably, the material usedtransmits both fluid flow and electrical energy; thus, materials withproperties midway between high-electrical conductivity metals and lowelectrical conductivity polymers are also contemplated, such as porouscarbon-filled polymers.

Because the conductive solution, such as saline, is generally lesselectrically conductive than the previously described electrode metals(such as stainless steel), there are several steps that can optionallybe taken to avoid dissipating an excess of electrical energy in theresistance of saline. Optionally, hypertonic saline is used instead of“normal” or physiologic saline. By adding more sodium chloride to thewater it is possible to decrease the electrical resistivity of thesolution by a factor of 3 to 5. Preferred hypertonic (i.e., saturated)saline includes 14.6% sodium chloride (NaCl) at 37° C. and has aresistivity of 5.9 ohm-cm. This is in contrast to “normal” saline, whichis 0.90% NaCl, with resistivity of 50 ohm-cm at 37° C. (bodytemperature).

In yet another alternative embodiment, shown in FIG. 21, a wireelectrode 48 is included in the first and second arms of the device. Asshown in the figure, the wall of each of the hollow electrodes 8 and 9comprises a porous polymer 47. Conductive solution 46 flows through theporous polymer wall. In previously described embodiments where theelectrodes are fabricated from metal, the RF energy is conducted to theelectrode-tissue interface by the metal in the wall of the electrodetubing. In the present embodiment, the metal is replaced by porouspolymer, and a “replacement” electrical conductor can be used to provideRF energy to the inner wall of the porous polymer near the tissue to betreated. Electrical energy is supplied to the first electrode 8 from awire electrode 48 that is preferably made of a metal such as platinumthat resists corrosion. This wire is insulated by a sheath 49 of somenon-conductive polymer such as Teflon™. The second electrode is suppliedRF electrical energy by exposed electrode wire 50 which is insulated bysheath 51. Preferably, the outer surface of the porous polymer isinsulated by another polymer coating 45, similar to the coating forporous metal electrodes, to keep conductive solution from flowing out ofthe first and second arms to locations where treatment is not desired.In this embodiment, the RF field lines 52 run from the exposed wire 48through conductive solution, through the conductive solution in theporous polymer wall of the first electrode 8, through the solution gapand/or the blood vessel, to the corresponding elements of the device onthe opposing side of the blood vessel to the second electrode's exposedwire 50. Alternatively, this porous polymer is fabricated from a solidpolymer tube or hollow member that has mechanically or laser-drilledsmall diameter holes in it.

The frequency of the electrical energy is typically 500 kHz, and thepower is typically in the range of about 10 to about 150, preferably inthe range of about 30 to about 70 watts. A typical range of conductivesolution flow rates is about 18-270 cc/hr. In a preferred embodiment,the total flow rate of conductive solution to both electrodes isapproximately determined as 1.8 times the power in watts, with theresult in cc/hr.

As discussed above, an RF source provides energy through the conductors,to the electrodes of the device. The RF source can be provided as agenerator, as described. Alternatively, the source can be configured tobe received within or attached to the housing of the device.

Optionally, the invention is provided with a cutting mechanism,indicated in the figures generally as 7. Preferably, the cuttingmechanism 7 is independently movable from the first or second arm, orboth. As described herein, the cutting mechanism serves to cut tissuepreferably after application of RF energy, such that the tissue has beencoagulated. Cutting tissue after coagulation reduces risk of bleedingfrom the tissues, especially with respect to highly vascularized tissuesuch as the liver, during treatment. However, it will be understood thatthe invention does not require tissue coagulation prior to cutting, forexample in situations where bleeding is not a concern.

The cutting mechanism of the invention is preferably provided in theform of a sharp blade. However, it is apparent from the presentdescription that the cutting mechanism need not be sharp, especiallywhen the cutting mechanism is supplied with RF energy, as describedbelow. In another embodiment, the cutting mechanism can be provided inthe form of a wire. In yet another embodiment, the cutting mechanism isnot itself sharp, but cuts tissue through the use of RF energy, asdescribed herein.

Optionally, the device is configured to supply the cutting mechanism 7with RF energy. Moreover, the device can be configured to allow thedevice to be switched between a bipolar mode in which RF energy issupplied to the first electrode, and a second bipolar mode in which RFenergy is supplied to the cutting mechanism 7. FIGS. 22 a and 22 billustrate this embodiment of the invention. FIG. 22 a shows thesituation during treatment of blood vessel 24 (e.g., coagulation), witha switch 42 configured to provide RF energy to the first electrode 8. Inthis operating mode, one of the two electrical paths is connected to thefirst electrode 8, and the lower electrical connection is made to thesecond electrode 9. After the vessel has been coagulated and it isdesired to cut the sealed vessel, FIG. 22 b shows switch 42 to operatethe device in a second mode, wherein the electrical connection thatpreviously supplied first electrode 8 in FIG. 22 a with RF energy is nowconnected to the cutting mechanism 7. In this mode, as cutting mechanism7 moves into contact with the sealed vessel, the edge of the bladeconcentrates the RF field so that the RF energy aids in the cutting ofthe tissue. This feature is intended to provide improved cuttingefficiency and minimize the effects of the blade becoming progressivelymore dull with use and less able to cut cleanly with minimal force.

The cutting mechanism of the invention can be provided in a variety ofsuitable configurations to achieve cutting of the tissue. FIGS. 23 athrough 23 e illustrate a number of alternative shapes for the cuttingmechanism, when provided in the form of a blade, with the arrowindicating the direction of cutting motion. As shown, the cuttingmechanism can provide a right angle straight edge (FIG. 23 a), an anglededge with a recessed edge downward toward the platform portion 26 of thesecond arm (FIG. 23 b), an angled edge with a recessed edge upward (FIG.23 c), a two-faceted edge (FIG. 23 d), or a rounded edge (FIG. 23 e).The sharp edge 43 is shown as a bolder line for all five of thevariations shown. While it is intended that none of the additionalvariations of cutting mechanism shape would protrude beyond the distalelectrode (e.g., for safety reasons) the different shapes are allintended to provide potentially improved cutting by recessing some partof the leading sharp edge. Other suitable shapes can be utilized toachieve the desired cutting according to the invention, and the shapesshown are illustrative only and should not be considered limiting.

As discussed herein, the cutting mechanism comprises an optionalcomponent of the device, to be used when the operator desires to cut atissue or blood vessel during treatment. When the device is providedwithout a cutting mechanism, the first and second arms can be fabricatedsuch that they do not include a slot to allow passage of the cuttingmechanism through the arm and thereby through tissue. In thisembodiment, the first and second arms are preferably provided in a“paddle-like” form, with varying amounts of roundness to the corners.This embodiment is depicted in FIGS. 24 and 25. FIG. 24 shows aschematic representation of a paddle-like electrode connected to aconductor for connection to a radiofrequency source. In this embodiment,the electrode surface 71 is provided with solution infusion openings 72on its face. FIG. 25 shows a schematic representation of a paddle-likeelectrode configuration, showing the first and second electrodes, 8 and9, positioned with a blood vessel 24 therebetween, and conductors 22 and23. As shown, the electrodes are preferably substantially the same size.

Preferably, the electrodes of this embodiment are hollow, to allow theflow of conductive solution, and with thin walls to allow the passage ofthe solution through to tissue. The passage of conductive solution isthrough either (1) small holes in solid metal or solid polymer (e.g., asshown in FIG. 24) or (2) micro- or macroporosity in metal or polymer. Ifsolid or porous polymer is used, then an internal “replacement”electrode wire can be used to provide RF close to the area where thereis tissue (as previously described with respect to porous polymerelectrodes). External portions of electrodes made with porous materialsare preferably insulated electrically and made impervious to keepconductive solution from weeping out where not desired. One advantage ofusing paddle-like electrodes with otherwise larger surface areas is thatthe larger electrode areas can provide lower impedance to RF power andThereby faster treatment times.

Use

The device of the invention can be used to coagulate and cut bodytissues, such as a blood vessel, in a variety of applications. Exemplaryapplications are described herein, without intending to be limitedthereto. Further, it is understood that the description herein can beused to treat a number of body tissues, and the invention is not limitedto treatment of tissues provided as examples.

FIG. 26 shows the coagulation and cutting pattern when the device isused on a blood vessel of diameter small enough to be coagulated and cutwith a single pass. FIG. 26 a is oriented to view the blood vessel 24and first electrode 8 when looking in a distal direction from thehousing and down the tubular member 6. In this embodiment, the operatorpositions the device, the blood vessel is compressed, then RF isapplied, resulting in the coagulation pattern shown in FIG. 26 b ascoagulation zone 39. The coagulation zone 39 is shown as smaller thanthe total exposed metal electrode surface area, though it could belarger than the metal area. This is not a critical aspect of theinvention, since the size of the coagulation zone is under the directcontrol of the surgeon who will typically use visual feedback (e.g.,color) to determine when tissue has been adequately treated. The size ofthe coagulation zone is determined by a number of factors, including thelength of time that the RF energy is applied, the power level of the RF,the conductive solution flow rate, the type and composition of thetissue, and the tissue compression force.

After cutting the blood vessel with the cutting mechanism 7, the resultis shown in FIG. 26 b, as two separate pieces of the blood vessel 24. Inthe coagulation zones 39, the opposite walls of the blood vessel 24 arebonded together so that no blood flows from the edges of the cut.

FIG. 27 shows how the device can be used to coagulate and cut a largerblood vessel. As shown in the first of four figures, 18 a, the device ispositioned and a U-shaped coagulation zone 39 is generated. The resultof this treatment is shown as 27 b, the U-shaped coagulated zone 39,with a cut 40 in between. In order to coagulate and cut again tocomplete the vessel transection, FIG. 27 c shows how the device ispositioned up into the cut 40 which has been spread apart by theplatform portion 26 of the second arm. After compression and applicationof RF energy, followed by another cutting action, the transected vesselappears approximately as shown in FIG. 27 d, with the final coagulationzone shown as 39. The coagulation zone 39 shown for the two-stepprocedure is only schematic and not intended to be a precise rendering.A larger vessel could also be sealed by approaching the vessel from theopposite side for the second seal, instead of from the same side, asjust described.

FIG. 28 shows an alternative way that the device can be used to treattissue that is not grasped between the two electrodes, but rather islocated in a noncoaptive manner adjacent to the distal end surface ofthe tips of the two electrode loops which, as shown in FIG. 28, alongwith other drawings, each comprise a spherical distal end surface. Thistype of operation is sometimes referred to as “coagulative surfacepainting.” With the first arm advanced distally, but not all the wayforward (i.e., toward the second electrode), and both RF energy deliveryand conductive solution flow turned on, the electrical field lines 36are schematically shown, extending from the tip of first electrode 8 ofthe first arm, through tissue and conductive solution, to secondelectrode 9 of the second arm. The surface of the conductive solution 35that has exited from the small holes extends downward in the directionof gravity to wet the surface 41 of the tissue. Vapor bubbles 37 may ormay not be present in the conductive solution as a result of heatgenerated by the RF energy. The device need not be oriented as indicatedin the figure for this mode of tissue treatment to occur; that is, thedevice can be used to treat tissue that is positioned above the device,since conductive solution will wet both the metal electrode and tissuesurfaces, even in opposition to the force of gravity. The sides of thedevice could also be used to perform coagulative painting. In such anembodiment, the sides of the electrodes are provided with sufficientsurface area to achieve the desired coagulative effect.

In a preferred embodiment, the device includes a locking mechanism. Oncethe optimum separation distance is achieved between the first and secondelectrodes, further movement of the first electrode is prevented byengaging an electrode locking mechanism that locks the position of theelectrode. In one embodiment, this locking mechanism is located on thehousing near the actuation member 2 (shown in FIGS. 1 and 2) that movesthe first arm translationally. The locking mechanism is used toselectively lock and unlock the first arm in a desired position. In use,the physician determines the optimum distance between the arms, basedupon visual feedback relating to how the end effector region of thedevice is interacting with tissue as the separation distance of thefirst and second arms is changed. For example, once the arm is locked inposition it would be easier for the physician to “paint” the surface ofa heavily bleeding organ, such as liver, without being concerned aboutthe electrode moving and losing the desired effect. The lockingmechanism also prevents the first electrode from inadvertentlycontacting the second electrode during use (e.g., during application ofRF energy). Alternatively, the locking mechanism is provided in theactivation member 2.

The locking mechanism is provided to lock one, or both of the arms. Whenthe device includes a first arm that is translationally movable, and asecond, stationary arm, the locking mechanism is provided to selectivelylock the first arm in a desired position. In turn, when the deviceincludes a second arm that is translationally movable, the lockingmechanism is provided to selectively lock the second arm in a desiredposition. Alternatively, when both arms are translationally movable, thelocking mechanism can selectively lock or unlock one or both of themovable arms.

Generally, as the first and second electrodes are moved closer together,a larger fraction of the conductive solution flow may boil, leading to a“hotter” tissue surface temperature. Conversely, as the electrodes arepositioned further away from each other, a smaller fraction of theconductive solution will boil, leading to a lower surface temperatureeffect.

In another embodiment, the device is capable of treating areas of thebody that are difficult to reach anatomical sites. In this embodiment,the device is provided with the ability to articulate or flex, to allowthe end effector region of the device to access areas of the bodyrequiring treatment that may be difficult to reach using minimallyinvasive or noninvasive techniques. As used herein, “articulate” meansthe tubular member is capable of moving about a joint or a jointed areaas described herein. In one preferred embodiment, the tubular member 6is provided with the ability to articulate, to allow the operator tomaneuver the device within the patient's body to reach the treatmentsite. Alternatively, the tubular member 6 can be angled or flexible, tofacilitate engaging a tissue from a selected approach position.

FIGS. 29 and 30 show one preferred embodiment of this device. As shownin FIG. 29, tubular member 6 includes an articulation zone 53 that islocated a predetermined distance from the distal end of the device. Inone embodiment shown in the figures, the area of the tubular member 54that is located between articulation zone 53 and the first arm of thedevice is rigid, and the area of the tubular member 55 that is locatedon the proximal side of the articulation zone is also rigid. Within thearticulation zone 53 is a rib construction of polymer ribs 56 separatedby air gaps 57. Other suitable constructions of the articulation zone 53are possible to achieve articulating movement of the tubular member.Alternatively, in an embodiment not shown, the areas of the tubularmember 54 and 55 are flexible. Additionally, the device includes atleast one articulation zone 53 and can include multiple articulationzones, as desired.

In one embodiment, rotatable knob 58 is located on the housing tocontrol movement of the articulation zone 53, and thereby controlarticulation of the device. As rotatable knob 53 is rotated by smallincremental amount, the articulation zone 53 bends a correspondinglysmall incremental amount. This bending or articulating is shown in FIG.30. When the rotatable knob 58 is rotated through a series of detents,the articulation zone 53 goes through a series of small incrementalbends, for example, of perhaps 5 degrees of arc per increment. The firstoffset view of the angled end effector 59 is at an angle of 30 degrees,and the second offset view of the end effector 60 is at an angle of 60degrees. The enlarged top view of the articulation zone 53 shows theribs 57 and gaps 56 during such articulating movement. When thearticulation zone bends, the diameter of gaps 56 decreases on one sideof the tubular member, and increases on the opposite side of the tubularmember.

The invention has been described as a bipolar surgical device, wherebyRF energy is supplied to the first and second electrodes, or to one ofthe electrodes and the cutting mechanism. Alternatively, the device canbe provided as a monopolar surgical instrument. In this embodiment, onlyone of the first or second electrode is provided with RF energy and aflow of conductive solution. In one preferred embodiment, the first,translationally movable arm containing the first electrode is providedwith conductive solution and RF as previously described. According tothis embodiment, the second arm is provided as a structural componentonly and is not provided with solution or electrical energy. In analternative preferred embodiment, the second electrode is provided withconductive solution and RF energy, as previously described. According tothis embodiment, the first arm is provided as a structural componentonly and is not provided with conductive solution or electrical energy.When the device is used as a monopolar device, the second electrode isprovided as a pad placed under the patient, as a ground, or a dispersiveelectrode.

The invention contemplates alternative configurations for the first andsecond arms, and the first and second electrodes. In one embodiment, thefirst arm of the device is provided in the form of a spring-loaded balltip. As shown in FIG. 31, one configuration of the device includes afirst arm in the form of a ball tip and a second arm configured in apaddle-like form. The tubular member 61, which corresponds to tubularmember 6 of FIG. 1, comprises a non-conductive polymer and contains theouter sheath 62 of the ball shaft, also fabricated from a non-conductivepolymer. According to this embodiment, the first arm of the device isprovided in the form of outer sheath 62 of the ball shaft, and the firstelectrode is provided in the form of a ball 64. A spherical ball 64 ispositioned within outer sheath 62 and is partially held in place by arim 63 of the sheath 62. The second electrode is positioned within thesecond arm provided in the form of insulated spatula 65, that isattached to the tubular member 61 by a support member 66, alsopreferably insulated. In a preferred embodiment, the electrodes areconfigured such that the inner opposing surface area of each issubstantially the same size, such that the surface area of the ball thatcontacts tissue is substantially the same as the surface area of thesecond electrode (e.g., spatula). Preferably, the electrode surfaceareas that contact and treat tissue are provided in a 1:1 ratio.Preferably, ball 64 is fabricated from a suitable metal, such asstainless steel and the like.

FIG. 32 shows a top view of the embodiment of FIG. 31 with the balladvanced distally to compress the vessel 24 against the secondelectrode.

FIG. 33 shows a cross-sectional view of the embodiment shown in FIG. 31.The tubular member 61 contains the outer insulating sheath 62 of theball shaft, the rim 63 and the ball 64. The rim 63 is part of a tubularstructure 67 that conveys both electrical energy and a flow ofconductive solution, such as saline, to the tip of the ball. In apreferred embodiment, the rim and tubular structure 67 are fabricated ofa suitable metal, such as stainless steel and the like. Conductivesolution, such as saline, flows from the housing in the tube 67, througha number of holes 68, past spring 70 which pushes the ball 64 againstthe rim 63, and out to the outer surface of the ball through gouges 75.The saline flow clings to the surface of the ball 64 and the rim 63through the action of surface tension. Saline flowing to the ball isshown as 69 as it passes through the holes in the tubular structure thatholds the spring in place. Spring 70 biases the ball 64 in a distaldirection, thereby urging the ball 64 against rim 63.

In one embodiment, the second electrode is comprised of a plate 71 witha plurality of holes 72 in it, that convey a flow of conductive solution74 down a lumen 73. The distal end portion 65 of the second armcomprises insulation covering the second electrode. Preferably, theplate 71 is metal.

FIG. 34 shows a cross-sectional view of the embodiment shown in FIG. 32.In this figure, the ball shaft is advanced proximally to compress theblood vessel 24 against the second electrode.

FIG. 35 is a top view of another embodiment of the invention. FIG. 36shows a view along line 36-36 of FIG. 35, looking proximally at thespherical surface of the ball 64. A radial series of small gouges 75 inthe rim 63 allows conductive solution to flow freely around the rim ofthe ball even when the spring is pressing the ball firmly against therim. Also shown are the tubular member 61, the outer sheath 62 of theball shaft, the lumen 73 in the second arm that conveys conductivesolution to the second electrode, and insulated conductor 76 thatconveys electrical energy to the second electrode 71.

FIG. 37 shows a view along line 37-37 of FIG. 35, looking in a distaldirection at the second arm of the device. According to this embodiment,the second arm includes second electrode 71 with holes 72, lumen 73, andconductor 76. The connection of conductor 76 to the distal electrode 71is not shown, but can be accomplished with a crimp of a tab of theelectrode 71 that would at least partially wrap around the conductorbefore crimping.

FIG. 38 is an end view of the distal end of the device, showing theblood vessel 24, the insulated covering 65 of the second arm, thetubular member 61 and the metal rim 63.

The ball embodiment of the invention provides a combination ofadvantages. For example, if the ball becomes clogged with char it caneasily be unclogged by pressing the ball distally against the secondarm. As the ball is pushed against any solid object, the spring 70compresses and the ball moves proximally to a position behind the rim63, thus breaking off any adherent char. This unclogging feature is notintended to be routinely used, since the presence of saline normallyprevents the creation of any char. However, there may be circumstanceswhen the physician may inadvertently misuse the device by excessivelyturning up the power or turning down the flow rate, which might resultin boiling off all the flow off saline, drying out the “wetness” of thedevice and causing char formation as the tissue temperature risessignificantly above 100° C.

Preferably, when the first electrode of the device is provided in theform of a ball 64, the second arm is shaped with a concave surfacefacing the convex shape of the first electrode. This “matching” ofelectrode shapes provides improved electrode-tissue contact and hencefaster and more uniform tissue coagulation. Alternatively, the secondelectrode of the device is provided in the form of a ball 64 (FIG. 39),in which emboodiment, the first arm can be shaped with a concavesurface.

The invention provides a combination of advantages over electrosurgicaldevices in the art. The device provides tissue coagulation and cuttingwithout tissue desiccation, sticking, perforation, smoke formation, charformation, or thermal spread of high temperatures. Further, theinvention provides electrodes of a variety of shapes and orientationsthat are supplied with a flow of saline in order to maintain theelectrode-tissue interface continuously wetted during the application ofRF energy. This “wet” electrode design will limit the peak tissuetemperature to 100° C. or less and prevent tissue sticking, tissueperforation, smoke formation, char formation, and high temperaturethermal spread. These advantages lead to faster, easier and safersurgical procedures.

Further, the device of the invention provides the ability to treattissue and vessels in hard-to-reach places. One preferred configurationof the device as a tubular, angled coagulator with a movable firstelectrode and an optional movable cutting mechanism leads to theadvantage of a low profile both during insertion and during actuation,compared to scissors-type devices. The articulating end effector regionof the device also confers a significant advantage of being able toreach difficult anatomical sites. This ultimately leads to fastersurgical procedures, reduced cost and increased safety. Moreover, theability to access hard-to-reach areas of the body for treatment usingthe device may allow surgeons to perform noninvasive or at leastminimally invasive procedures. This in turn avoids risks associated withopen surgical procedures, such as risk of infection, longer healingtime, and the like.

The invention thus provides a multi-purpose instrument that can be usedto provide both vessel or tissue coagulation and cutting, plus surfacecoagulation for stopping surface bleeding without having to remove thedevice from the trocar.

The design of the device enables bipolar coagulation and cutting withouthaving to remove the device from its location at the target tissue. Thedevice can also optionally be used in the bipolar mode to performsurface coagulation or coagulative “painting” with the space between thebipolar electrodes empty of tissue. The flow of saline is effective inachieving good coupling of RF energy to tissue even when used in thispainting mode.

Additionally, the invention provides a device that can be used as amonopolar or bipolar device, and is switchable between the two modes.

The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it will be apparent toone of ordinary skill in the art that many variations and modificationsmay be made while remaining within the spirit and scope of theinvention.

All publications and patent applications in this specification areherein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually incorporated by reference.

1. A bipolar electrosurgical device to treat tissue by moving along a tissue surface in a presence of radio frequency energy and a fluid provided simultaneously from the device, the device comprising: an end effector comprising a first stationary electrode tip and a second stationary electrode tip which are not movable relative to one another; the first electrode tip comprising a spherical tissue treating surface; the second electrode tip comprising a spherical tissue treating surface; at least one fluid exit to provide fluid to the first electrode tip; at least one fluid exit to provide fluid to the second electrode tip; a first fluid delivery lumen in fluid communication with the at least one fluid exit to provide fluid to the first electrode tip; and a second fluid delivery lumen in fluid communication with the at least one fluid exit to provide fluid to the second electrode tip.
 2. The device of claim 1 wherein: the first electrode tip and the second electrode tip are parallel.
 3. The device of claim 1 wherein: the first electrode tip and the second electrode tip are in a side-by-side arrangement.
 4. The device of claim 1 further comprising: a cutting mechanism.
 5. The device of claim 4 wherein: the cutting mechanism comprises a sharp edge.
 6. The device of claim 1 wherein: the first electrode tip and the second electrode tip are of substantially a same size.
 7. The device of claim 1 wherein: the first electrode tip and the second electrode tip are of substantially a same shape.
 8. The device of claim 1 wherein: the first electrode tip comprises an exposed surface area for treating tissue; the second electrode tip comprises an exposed surface area for treating tissue; and the first electrode tip exposed surface area and the second electrode tip exposed surface area are of substantially a same size.
 9. The device of claim 1 wherein: the at least one first fluid exit is located proximal to the spherical tissue treating surface of the first electrode tip; and the at least one second fluid exit is located proximal to the spherical tissue treating surface of the second electrode tip.
 10. The device of claim 1 wherein: at least one of the at least one first and second fluid exits is at least partially defined by the first and second electrode tips, respectively.
 11. The device of claim 1 wherein: the at least one fluid exit to provide fluid to the first electrode tip further comprises a plurality of fluid exits to provide fluid to the first electrode tip; and the at least one fluid exit to provide fluid to the second electrode tip further comprises a plurality of fluid exits to provide fluid to the second electrode tip.
 12. The device of claim 1 further comprising: a proximal fluid delivery lumen in fluid communication with the first fluid delivery lumen and the second fluid delivery lumen.
 13. The device of claim 1 further comprises: the first fluid delivery lumen in fluid communication with the at least one fluid exit to provide fluid to the first electrode tip passing through a first arm; and the second fluid delivery lumen in fluid communication with the at least one fluid exit to provide fluid to the second electrode tip passing though a second arm.
 14. The device of claim 1 wherein: the end effector comprises a noncoaptive end effector to treat the tissue other than by grasping the tissue.
 15. The device of claim 1 wherein: the fluid comprises an electrically conductive fluid.
 16. The device of claim 1 wherein: the at least one fluid exit to provide fluid to the first electrode tip has a diameter less than a diameter of the first fluid delivery lumen, and the at least one fluid exit to provide fluid to the second electrode tip has a diameter less than a diameter of the second fluid delivery lumen.
 17. The device of claim 1 wherein: the at least one fluid exit to provide fluid to the first electrode tip has a smaller opening area than an opening area of the first fluid delivery lumen, and the at least one fluid exit to provide fluid to the second electrode tip has a smaller opening area than an opening area of the second fluid delivery lumen. 